Previously, SSL_ECDH_METHOD consisted of two methods: one to produce a
public key to be sent to the peer, and another to produce the shared key
upon receipt of the peer's message.
This API does not work for NEWHOPE, because the client-to-server message
cannot be produced until the server's message has been received by the
client.
Solve this by introducing a new method which consumes data from the
server key exchange message and produces data for the client key
exchange message.
Change-Id: I1ed5a2bf198ca2d2ddb6d577888c1fa2008ef99a
Reviewed-on: https://boringssl-review.googlesource.com/7961
Reviewed-by: David Benjamin <davidben@google.com>
f4ce8e5324